WDB-178 is an investigational therapeutic agent in the preclinical phase of development, originated by Revolution Medicines, Inc..[1] It is classified as a non-degrading molecular glue and is designed to target the oncogenic KRAS G12C protein, a well-validated driver in various human cancers. The mechanism of action of WDB-178 is understood to be as a KRAS G12C inhibitor, operating through Revolution Medicines' proprietary tri-complex inhibitor platform.[2] This platform distinctively targets the active, GTP-bound conformation of RAS proteins, commonly referred to as RAS(ON). The therapeutic strategy involves inducing the formation of a ternary complex comprising WDB-178, an intracellular chaperone protein (such as cyclophilin A), and the RAS(ON) target protein. This tri-complex formation is intended to sterically hinder the interaction of KRAS G12C(ON) with its downstream effector proteins, thereby abrogating oncogenic signaling pathways.[4]
Given its target, WDB-178 holds therapeutic potential for a range of neoplasms characterized by KRAS G12C mutations.[1] The novel approach of targeting KRAS(ON) may confer advantages over existing KRAS G12C inhibitors that primarily bind the inactive GDP-bound (OFF) state, particularly in the context of overcoming intrinsic or acquired resistance mechanisms.[9] WDB-178 represents a next-generation strategy in KRAS G12C inhibition, leveraging a scientifically validated platform technology aimed at drugging the active, oncogenic form of RAS. This approach addresses a significant unmet medical need in the landscape of KRAS-mutant cancers, where existing therapies face limitations. The classification of WDB-178 as a "non-degrading molecular glue" [1] and its development by Revolution Medicines, a company with a strong portfolio of RAS(ON) tri-complex inhibitors [2], strongly suggests a mechanism distinct from simple protein degradation and aligns with the company's focus on inhibiting the active RAS state.[2]
The investigational compound is designated as WDB-178, with WDB178 also listed as a synonym.[1]
WDB-178 is categorized as a "non-degrading molecular glue".[1] Molecular glues are small molecules that function by inducing or stabilizing protein-protein interactions (PPIs).[14] Unlike degradative molecular glues (e.g., certain immunomodulatory imide drugs or PROTACs – Proteolysis Targeting Chimeras) that typically recruit E3 ubiquitin ligases to tag the target protein for proteasomal degradation, non-degrading molecular glues modulate the target protein's function, conformation, or interactions with other proteins without causing its degradation.[14] This distinction is critical as it implies a different pharmacological outcome and potentially different pharmacokinetic/pharmacodynamic (PK/PD) profiles and off-target considerations compared to protein degraders.
WDB-178 is being developed by Revolution Medicines, Inc., a clinical-stage precision oncology company.[2] The company's primary focus is on the development of novel targeted therapies for RAS-addicted cancers, with significant emphasis on inhibiting elusive frontier targets within the RAS and mTOR signaling pathways.[2] A cornerstone of Revolution Medicines' approach is its "Tri-Complex Inhibitor Platform." This platform is specifically engineered to target the active, GTP-bound state of RAS proteins (RAS(ON)), which has historically been challenging to drug.[2]
Revolution Medicines has a pipeline of RAS(ON) inhibitors, including daraxonrasib (RMC-6236, a RAS(ON) multi-selective inhibitor), elironrasib (RMC-6291, a RAS(ON) G12C-selective inhibitor), and zoldonrasib (RMC-9805, a RAS(ON) G12D-selective inhibitor), which are currently in clinical development.[2] The established expertise and the progression of these related compounds through preclinical and clinical development provide a robust scientific foundation and a degree of validation for the therapeutic strategy likely employed by WDB-178. The consistent focus on RAS(ON) targets and the application of the tri-complex mechanism across their pipeline strongly suggest that WDB-178, as a KRAS G12C inhibitor from this company, leverages this well-characterized and innovative platform.[2]
The KRAS gene, a member of the RAS superfamily of small GTPases, is one of the most frequently mutated oncogenes in human cancers, playing a critical role in tumor initiation, progression, and maintenance.[8] RAS proteins, including KRAS, function as molecular switches, cycling between an inactive GDP-bound (OFF) state and an active GTP-bound (ON) state.[12] In the ON state, KRAS interacts with various downstream effector proteins (e.g., RAF kinases, PI3-kinases) to activate signaling pathways that regulate cell proliferation, survival, and differentiation.[13]
Oncogenic mutations in KRAS, such as the G12C substitution (glycine to cysteine at codon 12), impair the intrinsic GTPase activity of the KRAS protein and/or render it insensitive to GTPase-activating proteins (GAPs). This results in a constitutive accumulation of KRAS in the active GTP-bound state, leading to aberrant and continuous downstream signaling that drives uncontrolled cell growth and malignant transformation.[8]
The KRAS G12C mutation is particularly prevalent in certain cancer types, most notably in approximately 13-15% of non-small cell lung cancers (NSCLC), 3-5% of colorectal cancers (CRC), and a smaller fraction of pancreatic and other solid tumors.[8] For decades, KRAS was considered "undruggable" due to its high affinity for GTP (picomolar range) and the smooth, featureless protein surface in its active state, which lacked obvious pockets for small molecule binding.[3]
Recent advancements in drug discovery have led to a paradigm shift with the development and FDA approval of covalent inhibitors specifically targeting the mutant cysteine residue in KRAS G12C, such as sotorasib and adagrasib.[3] These first-generation inhibitors function by binding to and trapping KRAS G12C in its inactive, GDP-bound (OFF) state, thereby preventing its activation and subsequent signaling.[7]
While these KRAS(OFF) inhibitors have demonstrated clinically meaningful activity and represent a significant therapeutic advance, their efficacy is not universal. A substantial proportion of patients do not respond, and among initial responders, acquired resistance frequently emerges, limiting the durability of clinical benefit.[3] Mechanisms of resistance can include secondary KRAS mutations, alterations in upstream or downstream signaling pathway components, or histologic transformation.[12] The development of resistance to KRAS(OFF) inhibitors underscores the unmet medical need for novel therapeutic strategies with distinct mechanisms of action. Targeting the active KRAS(ON) state, as WDB-178 is designed to do, represents one such innovative approach to potentially overcome these limitations.
WDB-178 is an inhibitor specifically targeting the KRAS G12C mutant protein.[1]
The compound is classified as a "non-degrading molecular glue".[1] This designation implies that WDB-178 functions by inducing or stabilizing a protein-protein interaction involving KRAS G12C, which ultimately leads to the inhibition of its oncogenic function without causing its proteasomal degradation.[14] This non-degradative mode of action contrasts with that of PROTACs or other degradative molecular glues, which aim to eliminate the target protein. The pharmacological consequence of non-degradation may include differences in the duration of action, potential for off-target effects related to the ubiquitin-proteasome system, and distinct resistance profiles.
The specific mechanism of WDB-178 is understood through the lens of Revolution Medicines' validated "Tri-Complex Inhibitor Platform," which targets the active RAS(ON) state.[2]
The non-degrading nature of WDB-178, functioning via steric blockade of effector binding as part of a tri-complex, offers a distinct pharmacological approach compared to inhibitors that induce target degradation or those that only bind the inactive KRAS(OFF) state. This could translate to a different spectrum of efficacy, resistance mechanisms, and safety considerations.
The development of RAS(ON) inhibitors like WDB-178 addresses the limitations observed with first-generation KRAS(OFF) inhibitors. The table below contrasts these mechanisms:
Feature | KRAS(OFF) Inhibitors (e.g., Sotorasib, Adagrasib) | RAS(ON) Tri-Complex Inhibitors (e.g., WDB-178, Elironrasib) |
---|---|---|
Target RAS State | Inactive, GDP-bound (OFF) state 7 | Active, GTP-bound (ON) state 2 |
Mechanism of Action | Covalent binding to G12C, trapping KRAS in OFF state 3 | Forms a tri-complex with a chaperone protein (e.g., CypA) and KRAS(ON), sterically blocking effector interactions 4 |
Involvement of Chaperone | No | Yes (e.g., Cyclophilin A) 2 |
Primary Mode of Inhibition | Covalent trapping of inactive state 3 | Steric blockade of active state signaling (may be covalent for G12C variants like elironrasib) 4 |
Target Degradation | No | No (non-degrading molecular glue) 1 |
Known Resistance Addressed | Aims to overcome resistance due to KRAS remaining in or reverting to ON state; targets the continuously signaling form 5 | Potentially overcomes resistance mechanisms that reactivate RAS signaling or bypass KRAS(OFF) inhibition 5 |
This comparative framework underscores the distinct approach of WDB-178 and its platform, aiming to inhibit the direct driver of oncogenic signaling, the KRAS(ON) protein.
Specific in vitro or in vivo efficacy, pharmacokinetic (PK), pharmacodynamic (PD), or detailed safety data for WDB-178 itself are not extensively available in the public domain through the provided research materials, beyond its classification as a preclinical compound targeting KRAS G12C.[1] The Synapse platform indicates the existence of proprietary data ("100 Clinical Results associated with WDB-178. Login to view more data"), but this is not accessible.[1] This lack of detailed public information is characteristic of compounds in the early stages of preclinical development, where data is often disclosed progressively at scientific conferences or in publications as development milestones are reached.
Given the shared platform technology and target class, the preclinical profile of WDB-178 can be inferred from data reported for analogous RAS(ON) tri-complex inhibitors developed by Revolution Medicines, notably elironrasib (RMC-6291, a KRASG12C(ON)-selective inhibitor) and related tool compounds like RMC-4998 and RMC-7977.
The consistent and potent preclinical efficacy demonstrated by multiple compounds from Revolution Medicines' RAS(ON) tri-complex platform, particularly the KRAS G12C-selective inhibitor elironrasib (RMC-6291), provides a strong basis to anticipate a promising preclinical profile for WDB-178. The shared platform technology, the specific KRASG12C(ON) target, and the likely similar chemical modality (tri-complex molecular glue) make the data from elironrasib and related tool compounds highly pertinent for inferring the potential characteristics of WDB-178.
Compound (Analogous to WDB-178) | Assay Type | Key Finding | Source Snippet(s) |
---|---|---|---|
Elironrasib (RMC-6291) | In Vitro | Median IC50 of 0.11 nM in KRASG12C mutant cells; inhibits ERK signaling; induces apoptosis. | 5 |
Elironrasib (RMC-6291) | In Vivo | 200mg/kg p.o. qd significantly inhibits tumor growth and induces immunological memory in murine tumor models. | 5 |
RMC-4998 (tool for RMC-6291) | In Vivo | In combination with RMC-7977, elicited cures in some KRAS G12C NSCLC preclinical models. | 10 |
Platform (KRASG12C Inhibitors) | In Vivo | Drives tumor regressions in xenograft models; overcomes RTK-mediated escape mechanisms. | 9 |
Platform (KRASG12C Inhibitors) | Mechanism | Forms tri-complex with CypA and KRASG12C(ON), sterically blocking effector binding. | 4 |
Elironrasib (RMC-6291) | Clinical (Prelim.) | Shows clinical activity in patients progressed on KRASG12C(OFF) inhibitors. | 5 |
RMC-7977 (tool for RMC-6236) | In Vivo | Overcame acquired resistance to RAS(OFF) and RAS(ON) G12C-selective inhibitors in advanced KRAS G12C-mutated NSCLC models. | 10 |
This table consolidates the preclinical evidence from related compounds, offering a structured view of the platform's capabilities and, by extension, the anticipated profile of WDB-178.
WDB-178 is being developed for the treatment of neoplasms (cancers).[1] Given its specific targeting of the KRAS G12C mutation, the primary therapeutic focus will be on solid tumors known to harbor this genetic alteration. These include, but are not limited to, non-small cell lung cancer (NSCLC), colorectal cancer (CRC), and pancreatic ductal adenocarcinoma (PDAC), which are among the most common KRAS G12C-mutated malignancies.[5]
WDB-178 is currently in the preclinical phase of development.[1] This stage typically involves extensive in vitro characterization (e.g., potency, selectivity, mechanism of action studies) and in vivo studies in animal models to assess efficacy, pharmacokinetics, pharmacodynamics, and safety/toxicology.
Following successful completion of preclinical studies, the anticipated development pathway for WDB-178 would involve:
The development trajectory of elironrasib (RMC-6291), another KRASG12C(ON) inhibitor from Revolution Medicines' tri-complex platform, provides a relevant precedent. Elironrasib has progressed from preclinical development into Phase 1/1b clinical trials (e.g., NCT05462717, NCT06128551, NCT06162221).[4] This progression suggests a viable path for WDB-178, assuming positive preclinical outcomes. Companies often leverage prior experience and regulatory interactions from platform-derived compounds to streamline the development of subsequent candidates.
Revolution Medicines, Inc. holds patents related to WDB-178.[1] While specific patent numbers for WDB-178 are not detailed in the provided snippets, it is standard practice for biopharmaceutical companies to secure robust intellectual property (IP) protection for their novel compounds and platform technologies. These patents likely cover the chemical matter of WDB-178, its method of use in treating KRAS G12C-driven cancers, and potentially aspects of the tri-complex inhibitor platform itself. The Synapse platform indicates "100 Patents (Medical) associated with WDB-178," which, for a preclinical compound, suggests a comprehensive patenting strategy covering the broader technology and its applications.[1] A strong IP portfolio is fundamental for protecting the innovation and securing the future commercial potential of WDB-178.
WDB-178 emerges from the provided information as a preclinical investigational agent with a scientifically compelling profile, primarily defined by its classification as a non-degrading molecular glue and its origin from Revolution Medicines' innovative tri-complex RAS(ON) inhibitor platform. This platform is designed to address the oncogenic KRAS G12C protein, a target of high significance in oncology.
The key differentiating factor for WDB-178 and its platform analogues is the ability to target the active, GTP-bound (ON) state of KRAS. First-generation KRAS G12C inhibitors target the inactive (OFF) state, and while they have provided clinical benefit, their efficacy is often limited by intrinsic and acquired resistance mechanisms that frequently involve the reactivation or persistence of KRAS(ON) signaling. By directly engaging KRASG12C(ON), WDB-178 has the potential to overcome these limitations and offer a more profound and durable inhibition of oncogenic signaling. The tri-complex mechanism, involving the recruitment of an intracellular chaperone like cyclophilin A to create a neomorphic binding surface on KRASG12C(ON), represents a novel chemical biology strategy. This approach may enable the drugging of targets previously considered intractable due to their surface characteristics in the active state. Furthermore, the oral bioavailability demonstrated by related compounds from this platform, such as elironrasib [5], suggests that WDB-178 may also be developed as an oral therapeutic, which would offer a significant advantage in terms of patient convenience and compliance.
Despite the promising rationale, the translation of preclinical findings to clinical success is a well-recognized challenge in drug development. The long-term safety implications of modulating chaperone proteins like CypA, and the overall tolerability of the tri-complex inhibitory approach in human subjects, will require meticulous evaluation in future clinical trials. The field of KRAS inhibition is intensely competitive, with numerous agents in development. For WDB-178 to establish a significant clinical niche, it will need to demonstrate clear advantages in terms of efficacy, safety, durability of response, or ability to overcome resistance compared to existing and emerging therapies.
If WDB-178 successfully navigates clinical development, it could represent a new therapeutic paradigm for patients with KRAS G12C-driven cancers, potentially as a monotherapy or as a crucial component of combination regimens. The robust preclinical efficacy, including tumor regressions and the overcoming of resistance, observed with analogous compounds from the Revolution Medicines platform, provides a strong foundation for the continued development of WDB-178.
Future research and disclosures will be critical. Specifically, the "non-degrading" nature of WDB-178 raises questions about the duration of target inhibition in vivo, particularly if the interaction is not covalent, and how this compares pharmacodynamically to covalent KRAS(OFF) inhibitors or to KRAS degraders. The persistent presence of a tri-complex, as opposed to target elimination by degraders, might also present a different immunogenic profile, which warrants investigation. These aspects will be important to monitor as more data on WDB-178 and related RAS(ON) inhibitors become available.
In conclusion, WDB-178 is a noteworthy preclinical candidate that embodies an advanced and scientifically rational approach to targeting the oncogenic KRAS G12C protein. Its development leverages a validated platform technology with the potential to address significant unmet needs in the treatment of KRAS-mutant cancers. The progress of WDB-178, alongside other RAS(ON) inhibitors from Revolution Medicines' pipeline, will be closely watched by the oncology community.
Published at: May 19, 2025
This report is continuously updated as new research emerges.